Foster had been impressive early in the game, collecting three tackles before he was hurt. Veteran Ray-Ray Armstrong took his place and notched six tackles over the rest of the game.

When Foster first suffered his injury, some on the team believed he may have broken his leg. Foster, in fact, feared the worst until he was able to eventually put some weight on it as he stood.

“It was pain(ful),” he told Nick Wagoner of ESPN.com. “I was a little scared. But at the same time, trust me, if you can’t put no pressure on it, then you should be worried. But when you put enough pressure on it, then you have got some hope. That’s all I was hoping for. It was painful, but at the same time I knew nothing was seriously damaged.”

Niners head coach Kyle Shanahan said Foster and the team dodged a bullet.

“It was definitely better than it seemed out there (on the field),” he said. “They thought at first it was possibly a tibia (fracture), and they came out and told me at halftime that it was negative (on X-rays), but he wasn’t good enough to go back in the game.”

The 49ers hope to have Foster back in the starting lineup Sunday in Seattle for the game, which is scheduled to begin at 1:25 p.m.